Re: bash conditional expressions

[Michael J. Baars]

On Fri, 2021-11-12 at 19:48 +0100, Andreas Schwab wrote:
>       FILE1 -nt FILE2  True if file1 is newer than file2 (according to
>                        modification date).
> 
> Andreas.
> 

So now we have a relation for 'older than' and for 'newer than', but how about 
'oldest' (executable), and 'newest' (executable)?

I could only come up with this:

unset y; for x in $(find bin -mindepth 1 -name "*"); do if [[ ${x} -nt ${y} ]]; 
then y=${x}; fi; done; echo newest: ${y};
y="bin"; for x in $(find bin -mindepth 1 -name "*"); do if [[ ${x} -ot ${y} ]]; 
then y=${x}; fi; done; echo oldest: ${y};

As you can see, the way the commands are initialized is not identical, because:

'-nt' returns a true when 'if file1 exists and file2 does not'  (y in     
initialized by the first condition evaluated)
'-ot' returns a true when 'if file2 exists and file1 does not'  (y is not 
initialized by the first condition evaluated)

When you try to selectively link new executables, I think it is important that 
you do not only have relations for 'older than' and 'newer than', but also 
consistent (identically initializated)
relations for 'oldest' and 'newest'.

Mischa.